Posts Tagged ‘Sleep’

Early Risers Crash Faster Than Night Owls

“Early to bed and early to rise makes a man healthy, wealthy and wise.” –Benjamin Franklin

Some people are “morning people”, functioning a little too well in the early a.m. hours, while others are “lazy” and can’t get anything done before the crack of noon. When we fast forward the clock a bit to midnight or later, the morning people are out cold, whereas those lazy individuals are just getting revved up.

In a new study researchers Christina Schmidt and Philippe Peigneux, both at the University of Liège in Belgium, and their colleagues first asked 16 extreme early risers and 15 extreme night owls to spend a week following their natural sleep schedule. Then subjects spent two nights in a sleep lab, where they again followed their preferred sleep patterns and underwent cognitive testing twice daily while in a functional MRI scanner.

It is tempting to assign the blame for these differences on mere habit, but what if there is an underlying biological explanation? Perhaps there are other subtleties at play here as well.

An hour and a half after waking, early birds and night owls were equally alert and showed no difference in attention-related brain activity. But after being awake for 10 and a half hours, night owls had grown more alert, performing better on a reaction-time task requiring sustained attention and showing increased activity in brain areas linked to attention. More important, these regions included the suprachiasmatic area, which is home to the body’s circadian clock. This area sends signals to boost alertness as the pressure to sleep mounts. Unlike night owls, early risers didn’t get this late-day lift. Peigneux says faster activation of sleep pressure appears to prevent early birds from fully benefiting from the circadian signal, as evening types do.

An early riser who wakes up at 5 a.m. will not crash at 3 in the afternoon. However, their brains are not as alert in the late afternoon compared to a night owl who wakes up at noon, and is then tested past 10 p.m. The main difference is that night owls will maintain a high level of attention for longer periods of time, not just different periods of time.

Are night owls taking advantage of a circadian signal, or have they somehow pushed the brain’s equivalent of a snooze button, delaying the chemical reaction which causes the “need to sleep right now” pressure?

We would like to see a version of this study done with those individuals who naturally need 25% less sleep than normal.

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That Magic Slumber Number

Scientists have been saying for years that 8 hours is the magic number needed for a good night’s rest. Most working Americans get less and it has a detrimental effect on health.

Ying-Hui Fu, Ph.D at the University of California, San Francisco along with a team of scientists* found a mother and daughter with a mutated gene (DEC2) which is somehow responsible for their ability to thrive on only 6 hours of sleep.

Scientists are still trying to unravel the mysteries of sleep.

Sleep remains a relatively inscrutable biological phenomenon. Scientists know that it is regulated in large part by two processes: 1) circadian rhythms—genetic, biochemical and physiological mechanisms that wax and wane during a 24 hour period to regulate the timing of sleep, 2) and homeostasis – unknown mechanisms that ensure that the body acquires over time the necessary amount of sleep, nudging it toward sleep when it has been deprived, prompting it out of sleep when it has received enough.

Genetically engineered mice who carried the mutated gene not only were getting less sleep in general, but also had a faster recovery time after a period of sleep deprivation.

The specific function of DEC2 remains elusive.

DEC2 could be involved in modulating “sleep quantity” alone, or it could be mediating both “sleep quantity” and “wakefulness-behavioral drive,” according to Fu. The latter drive, she says, is critical for the procurement of food, shelter, and mates and could be more potent in individuals with this mutation.

*Co-authors of the study are Christopher R. Jones, MD, at the University of Utah; Nobuhiro Fujiki, PhD, and Seiji Nishino, PhD, both of Stanford University; Ying Xu, PhD, and Jimmy Holder, MD, PhD, both at the time of the study in the Fu lab; Bin Guo, PhD, of the University of California, Berkeley; and Moritz J. Rossner, PhD, of the Max-Planck-Institute of Experimental Medicine.

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According to the study’s lead author, Wendy Troxel, PhD, Assistant Professor at the University of Pittsburgh School of Medicine, women who were stably married had the highest quality sleep measured objectively and subjectively, and these results persisted even after controlling for other known risk factors for sleep, including age, ethnicity, socioeconomic status, and depressive symptoms.

Well, ladies, what are you waiting for?

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Using Math To Take The Lag Out Of Jet Lag

There is a known connection between levels of light exposure, melanin, and proper circadian rhythms. The quickest way to adjust to a new time zone would be by applying bright light or no light at different points as a way of resetting the body’s internal clock. Researchers at Brigham and Women’s Hospital and the University of Michigan have developed a program to figure out all the specifics for you.

The program, which seeks to re-synchronize the body with its new environment, considers inputs like background light level and the number of time zones traveled. Then, based on a mathematical model, the program gives users exact times of the day when they should apply countermeasures such as bright light to intervene and reduce the effects of jet lag.

The real question on everyone’s mind is, “how well does it actually work”?

“This work shows how interventions can cut the number of days needed to adjust to a new time zone by half,” said co-author Daniel Forger.

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